It is not known precisely when Dutch traders began to import the mysterious golden material called Indian yellow. It appears in some Dutch paintings of the seventeenth century but does not seem to have found wider use in Europe until the late eighteenth.
The pigment, known in India since about the fifteenth century under the name purree, pun, or peon, seems to be of Persian origin. But what was this stuff, sold in hard, dirty-colored, ill-smelling balls? Speculation abounded, much of it lurid. In the nineteenth century the French colorman J.-F.-L. Merimee remarked on its smell of urine but was reluctant to entertain the notion, proposed by others previously, that the substance could really harbor such an ingredient. George Field in England was less circumspect, believing that it was made from the urine of camels; others deemed that the fluid came instead from snakes.
It was not until 1883 that these rumors were set right. The Indian T. N. Mukharji made inquiries in Calcutta after the origin of the yellow balls and was directed to the village of Mirzapur on the outskirts of the city Monghyr in northeast Bihar province. Here he discovered that certain (iwners "milkmen"--created the stuff from the urine of cows fed exclusively on a diet of mango leaves. The yellow solid precipitated from the liquid when it was heated. Pressed into lumps and dried, it was then shipped to Calcutta and Patna for sale. It seems that the entire output of the pigment from India to Europe came from this village.
Given no other source of nutrition for fear that it would diminish the output of the colorant, the mango-fed cows were in a very poor state of health—to the disgust of Monghyr's regular dairy farmers, who called the milkmen "cow destroyers." The discovery of the pigment's source helped accelerate its demise: the practices of' the milkmen were denounced as in-humane, and laws were passed to prohibit them. By 1890 the legislation in Bengal to prevent cruelty to animals had become sufficiently stringent to make the manufacture of Indian yellow illegal, and it had all but disappeared by 1908.
Urine is, however, just an incidental component of the pigment. The colorant is a calcium or magnesium salt of an organic acid released by the mango. Despite the unpromising appearance of the raw balls, the ground pigment is rather lovely, giving a deep golden yellow. Its properties are better suited to use as a watercolor than as an oil pigment.
[Bright Earth, Philip Ball, pages 138-139]